Interlayer film and laminated glass comprising the same

ABSTRACT

The present disclosure relates to an interlayer film for laminated glass comprising: (a) polyvinyl butyral (PVB) resin having an average molecular weight (Mw) as measured by Gel Permeation Chromatography (GPC) from about 175,000 to about 210,000 Dalton; and (b) about 30 to about 50 parts per hundred (pph) of a plasticizer. The interlayer film interposed between two glass sheets forms laminated glass having a pummel adhesion value that is greater in an outer area of the laminated glass than in a middle area of the laminated glass after the laminated glass has been maintained at 50° C. and 95% relative humidity (RH) for 28 days. The laminated glass exhibits improved durability and does not delaminate over time, even in the presence of high temperature and humidity conditions.

FIELD OF THE DISCLOSURE

The present technology relates to interlayer films and laminated glasscomprising the same. The interlayer films provide improved adhesiveproperties to laminated glass, thereby helping to avoid delamination ofthe glass.

BACKGROUND

Laminated glass is a type of safety glass that holds together whenshattered. An interlayer, typically made of polyvinyl butyral (PVB) orethylene-vinyl acetate (EVA), is included to between two or more layersof glass. The interlayer keeps the layers of glass bonded even when ifthe glass is broken, and its high strength prevents the glass frombreaking up into large sharp pieces. This produces a characteristic“spider web” cracking pattern when the impact is not enough tocompletely pierce the glass.

Laminated glass is often used when there is a possibility for humanimpact or where the glass could fall if shattered and also forarchitectural applications. For example, skylight glazing and automobilewindshields typically use laminated glass. In geographical areasrequiring hurricane-resistant construction, laminated glass is oftenused in exterior storefronts, curtain walls, and windows.

Laminated glass is also useful for increasing a sound insulation ratingof windows, e.g., it significantly improves sound attenuation comparedto monolithic glass panes of the same thickness. For this purpose, aspecial “acoustic PVB” compound can be used for the interlayer. In thecase of the EVA material, no additional acoustic material is required,since the EVA provides sound insulation. An additional benefit forlaminated glass for windows is the blockage of ultraviolet radiation bythe PVB and EVA interlayer,

A problem with laminated glass is that under high moisture and hightemperature conditions, the moisture tends to penetrate openings betweenglass layers and the interlayer. The moisture disrupts the hydrogenbonding between the interlayer (e.g., PVB sheets) and the glass layers,resulting in delamination of the laminated glass. Therefore,improvements in adhesive properties of the interlayer are needed toavoid delamination.

SUMMARY OF THE DISCLOSURE

The present disclosure relates to interlayer films for use in laminatedglass; and to laminated glass comprising the interlayer films. Theinterlayer films exhibit improved adhesive properties, which result inimprovements in the quality and durability of the laminated glass thatincorporates the interlayer films. For example, delamination of theinterlayer films is avoided. The interlayer films result in laminatedglass being surprisingly resistant to high moisture and high temperatureconditions, even for prolonged periods. These improvements can beachieved, at least in part, by controlling the flow properties of theinterlayer, including polyvinyl butyral (PVB) having a particularaverage molecular weight in the interlayer, and by using metals salts,plasticizers, etc.

In one embodiment, the interlayer films of the present disclosureinclude:

-   -   (a) polyvinyl butyral (PVB) resin having an average molecular        weight (Mw) as measured by Gel Permeation Chromatography (GPC)        from about 175,000 to about 210,000 Dalton; and    -   (b) about 30 to about 50 parts per hundred (pph) of a        plasticizer;

wherein, the interlayer film interposed between two glass sheets formslaminated glass having a pummel adhesion value that is greater in anouter area of the laminated glass than in a middle area of the laminatedglass after the laminated glass has been maintained at 50° C. and 95%relative humidity (RH) for 28 days. The outer area of the laminatedglass is the area formed by the outer edges of the perimeter of a sheetof the laminated glass and extending inward toward the center of thesheet of the laminated glass by a distance of 5 mm; and the middle areaof the laminated glass is the area in the middle of the laminated glasshaving a size of 50 mm×50 mm.

In some instances, the interlayer film interposed between two glasssheets forms laminated glass having a pummel adhesion value that isessentially unchanged in the middle area of the laminated glass, evenafter the laminated glass is maintained at 50° C. and 95% relativehumidity (RH) for 28 days.

As already noted, the PVB resin of embodiments of the disclosuretypically has an average molecular weight from about 175,000 to about210,000 Dalton. In some instances, it can be useful if the PVB resinalso have at least 10 wt. % of PVB having a Mw of less than 50,000.

Non-limiting examples of plasticizers include monobasic acid esters,polybasic acid esters, organic phosphoric acids, organic phosphorusacids, and a mixture thereof.

The interlayer films of various embodiments may include metal salts, forexample, a sodium salt, a potassium salt, or a mixture thereof. Thetotal amount of sodium salt, potassium salt, or a mixture thereof maybe, for example, a positive amount up to about 80 parts per million(ppm) as sodium content, potassium content, or a mixture thereof. Insome instances, the sodium salt does not exceed 40 ppm as sodium contentand the potassium salt does not exceed 40 ppm as potassium content.

Finally, the instant disclosure relates to laminated glass comprisingthe interlayer films described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof example only, with reference to the attached figures, wherein:

FIG. 1 is a diagram showing an example of laminated glass;

FIG. 2(a) is an illustration of laminated glass, wherein the interlayerfilm has poor flow properties leading to delamination;

FIG. 2(b) is an illustration of laminated glass, wherein the interlayerfilm has good flow properties and therefore avoids delamination;

FIG. 3 is a flow diagram illustrating a process for manufacturing PVBresin;

FIG. 4 is a flow diagram illustrating a process for manufacturing aninterlayer film; and

FIG. 5 is a flow diagram illustrating a process for manufacturinglaminated glass.

It should be understood that the various aspects are not limited to thearrangements and instrumentality shown in the figures.

DETAILED DESCRIPTION OF THE DISCLOSURE

In one embodiment, the interlayer films of the present disclosureinclude:

-   -   (a) polyvinyl butyral (PVB) resin having an average molecular        weight (Mw) as measured by Gel Permeation Chromatography (GPC)        from about 175,000 to about 210,000 Dalton; and    -   (b) about 30 to about 50 parts per hundred (pph) of a        plasticizer;

wherein the interlayer film interposed between two glass sheets formslaminated glass having a pummel adhesion value that is greater in anouter area of the laminated glass than in a middle area of the laminatedglass after the laminated glass has been maintained at 50° C. and 95%relative humidity (RH) for 28 days. The outer area of the laminatedglass is the area formed by the outer edges of the perimeter of a sheetof the laminated glass and extending inward toward the center of thesheet of the laminated glass by a distance of 5 mm; and the middle areaof the laminated glass is the area that is the area in the middle of thelaminated glass having a size of 50 mm×50 mm.

The interlayer films typically have a flow of at least 250 μm. The term“flow”, as used herein, is the deformation (reduction in thickness) whena load pressure is applied to the surface of the interlayer film in thethickness direction, upon heating from an initial temperature to a finaltemperature, measured using a thermomechanical analysis apparatus.

The flow of the interlayer films is typically at least 250 μm, and insome instances may be as high as 500 μm. In some instances, the flow ofthe interlayer films may be from 250 μm to 450 μm, from 250 μm to 400μm, from 250 μm to 350 μm, from 250 μm to 300 μm, from 255 μm to 500 μm,from 255 μm to 450 μm, from 255 to 400 μm, from 255 to 350 μm, from 255μm to 300, from 260 μm to 500 μm, from 260 to 450 μm, from 260 μm to 400μm, from 260 μm to 350 μm, or from 260 μm to 300 μm.

The PVB resin of the interlayer films of the present disclosuretypically has an average molecular weight from about 175,000 to about210,000 Dalton. In some instances, the PVB resin typically has anaverage molecular weight from about 175,000 to about 205,000 Dalton,about 175,000 to about 200,000 Dalton, about 180,000 to about 210,000Dalton, about 180,000 to about 205,000 Dalton, or about 180,000 to about200,000 Dalton.

In some instances, it can be useful for the PVB resin to include atleast 10 wt. % of PVB having a Mw of less than 50,000. Moreover, in somecases, the PVB resin includes at least 11 wt. %, at least 12 wt. %, orat least 13 wt. % of PVB having a Mw of less than 50,000. For example,the PVB resin may include about 10 to about 25 wt. % of PVB having a Mwof less than 50,000. In some instances, the PVB resin may include about11 to about 25 wt. %, about 11 to about 20 wt. %, about 12 to about 25wt. %, about 12 to about 20 wt. %, about 13 to about 25 wt. %, or about13 to about 20 wt. % of PVB having a Mw of less than 50,000.

In some instances, it can be useful for the PVB resin to have a degreeof butyralization of about 60 to about 80 mol. %. In some cases, thedegree of butyralization may be about 60 to about 75 mol. %, about 60 toabout 70 mol. %, about 65 to about 80 mol. %, about 65 to about 75 mol.%, or about 65 to about 70 mol. %.

As already noted, the interlayer films of the present disclosure caninclude one or more plasticizers. Non-limiting examples of usefulplasticiziers include monobasic acid esters, polybasic acid esters,organic phosphoric acids, organic phosphorus acids, and a mixturethereof. More specific yet non-limiting examples include dipropyleneglycol dibenzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate,triethylene glycol di-(2-ethylhexanoate), tetraethyleneglycoldi-(2-ethylhexanoate), triethylene glycol di-(2-ethylbutyrate),triethylene glycol diheptanoate, tetraethylene glycol diheptanoate,dihexyladipate, dioctyladipate, hexyl cyclohexyladipate,diisononyladipate, heptylnonyladipate, dibutylsebacate, triethyleneglycol bis(2-ethylhexanoate)(3GO), tetraethylene glycoldi-2-ethylbutyrate (4GH), bis[2-(2-butoxyethoxy)ethyl] adipate (D600)and a mixture thereof.

The interlayer films of the present disclosure can include about 30 toabout 50 parts per hundred (pph) of plasticizer. In some cases, theamount of plasticizer is from about 35 to about 50 pph or about 35 toabout 45 pph.

The interlayer films of the present disclosure may optionally include asalt, for example, a sodium salt, a potassium salt, or a mixturethereof. Non-limiting examples of sodium salts include sodiumperchlorate, sodium formate, sodium acetate, sodium 2-ethylbutyrate,sodium 2-ethylhexanoate, and a mixture thereof. Non-limiting examples ofpotassium salts include potassium perchlorate, potassium formate,potassium acetate, potassium 2-ethylbutyrate, potassium2-ethylhexanoate, and a mixture thereof. The interlayer films mayinclude only sodium salt(s), only potassium salt(s), or a combination ofboth sodium and potassium salt(s).

The total amount of sodium and/or potassium salt(s) may be about 10 toabout 80 parts per million (ppm) of sodium content, potassium content,or mixture thereof. In some instances, the total amount of sodium and/orpotassium salt(s) may be about 15 to about 80 ppm, about 20 to about 80ppm, about 30 to about 80 ppm, about 40 to about 80 ppm, about 45 toabout 80 ppm, about 10 to about 75 ppm, about 20 to about 75 ppm, about30 to about 75 ppm, about 40 to about 75 ppm, or about 50 to about 75ppm of sodium content, potassium content, or mixture thereof.

The total amount of sodium salt(s) may be about 10 to about 80 ppm,about 10 to about 70 ppm, about 10 to about 60 ppm, about 10 to about 50ppm, or about 10 to about 40 ppm sodium content. Similarly, the totalamount of potassium salt(s) may be about 10 to about 80 ppm, about 10 toabout 70 ppm, about 10 to about 60 ppm, about 10 to about 50 ppm, orabout 10 to about 40 ppm potassium content. Thus, in some instances, thetotal amount of sodium salt does not exceed 40 ppm as sodium contentand/or the total amount of potassium salt does not exceed 40 ppm aspotassium content.

The interlayer films of the instant disclosure, when interposed betweentwo glass sheets, form laminated glass that provides a pummel adhesionvalue that is greater in the outer area of the laminated glass than inthe middle area of the laminated glass after the laminated glass hasbeen maintained at about 50° C. and about 95% relative humidity (RH) for28 days. The outer area of the laminated glass is the area formed by theouter edges of the perimeter of a sheet of laminated glass extendinginward toward the center of the sheet of laminated by a distance of 5mm. The middle area of the laminated glass is the area that is the areain the middle of the laminated glass having a size of 50 mm×50 mm.

The total area and the thickness of the interlayer film can vary. Thearea of the interlayer film will typically be dictated by the size oflaminated glass in which the interlayer film is used. With respect tothickness, the interlayer film may have a thickness of about 0.3 mm toabout 1.5 mm. In some instances, the thickness may be about 0.4 to about1.5 mm, about 0.5 to about 1.5 mm, about 0.6 to about 1.5 mm, about 0.7to about 1.5 mm, about 0.8 to about 1.5 mm, about 0.9 to about 1.5 mm,about 1 to about 1.5 mm, about 0.3 to about 1.4 mm, about 0.3 to about1.3 mm, about 0.3 to about 1.2 mm, about 0.3 to about 1.1 mm, about 0.3to about 1 mm, or about 0.5 to about 1 mm.

The pummel adhesion value of the outer area of the laminated glasscomprising the interlayer films of the instant disclosure is greaterthan the pummel adhesion value of the middle area of the laminated glassafter the laminated glass is maintained at 50° C. and 95% relativehumidity (RH) for 28 days. For example, the pummel adhesion value may begreater by at least 1, at least 2, at least 3, at least 4, or at least5.

In some instances, the pummel adhesion value of the outer area of thelaminated glass is at least 7, after the laminated glass is maintainedat 50° C. and 95% relative humidity (RH) for 28 days. Similarly, thepummel adhesion value of the outer area of the laminated glass after thelaminated glass is maintained at 50° C. and 95% relative humidity (RH)for 28 days may be at least 8 or at least 9. Furthermore, the pummeladhesion level of the outer area of the laminated glass may be at least7, 8, or 9, and the pummel adhesion value of the outer area of thelaminated glass is greater than the pummel adhesion value of the middlearea of the laminated glass by at least 1, 2, 3, 4, or 5, after thelaminated glass is maintained at 50° C. and 95% relative humidity (RH)for 28 days.

The pummel adhesion value of the middle area of the laminated glassafter the laminated glass is maintained at 50° C. and 95% relativehumidity (RH) for 28 days may be 2 to 8. In some instances, the pummeladhesion value of the middle area of the laminated glass after thelaminated glass is maintained at 50° C. and 95% relative humidity (RH)for 28 days is 2 to 7, 3 to 8, 3 to 7, 4 to 8, or 4 to 7. Furthermore,the pummel adhesion value of the middle area of the laminated glass maybe 2 to 8, 2 to 7, 3 to 8, 3 to 7, 4 to 8, or 4 to 7; and the pummeladhesion value of the outer area of the laminated glass is greater thanthe pummel adhesion value of the middle area of the laminated glass byat least 1, 2, 3, 4, or 5, after the laminated glass is maintained at50° C. and 95% relative humidity (RH) for 28 days.

Furthermore, the pummel adhesion value of the outer area of thelaminated glass is typically higher after the laminated glass ismaintained at 50° C. and 95% relative humidity (RH) for 28 days thanbefore the laminated glass is maintained at 50° C. and 95% relativehumidity (RH) for 28 days. In other words, maintaining the laminatedglass at a temperature of 50° C. and 95% relative humidity (RH) for 28days results in the pummel adhesion value of the outer area of thelaminated glass increasing. The pummel adhesion value may increase by 1,2, 3, 4, or 5. For example, if the pummel adhesion value of the outerarea of the laminated glass is initially 4 (i.e., the pummel adhesionvalue before the laminated glass is maintained at 50° C. and 95%relative humidity (RH) for 28 days is 4), the pummel adhesion value mayincrease by 1, 2, 3, 4 or 5, to a pummel adhesion value of 5, 6, 7, 8,or 9 after the laminated glass is maintained at 50° C. and 95% relativehumidity (RH) for 28 days. Similarly, for example, an initial pummeladhesion value of 6 may increase to 7, 8 or 9; an initial pummeladhesion value of 7 may increase to 8 or 9; and an initial pummeladhesion value of 8 may increase to 9.

The instant disclosure not only relates to the interlayer films thatprovide improved pummel adhesion values to laminated glass sheets, butit also relates to the laminated glass sheets comprising the interlayerfilms. Typically, the size (area) of the laminated glass sheets willvary based on the use or application for the laminated glass sheets.Some uses or applications require larger pieces of laminated glasssheets (laminated glass having a larger area), for example, largewindows, walls, building exteriors, etc. On the other hand, some uses orapplications require smaller pieces of laminated glass sheets, forexample, mobile phones, computer screens, wristwatches, etc.

With respect to thickness, the laminated glass sheets can have athickness of about 2 mm to about 8 mm. In other words, the thickness oftwo sheets of glass and an interlayer film interposed between the twosheets of glass can be about 2 mm to about 6 mm, about 3 mm to about 6mm, about 4 mm to about 6 mm, about 2 mm to about 5 mm, about 3 mm toabout 5 mm, or about 4 mm to about 5 mm. Each individual sheet of glassof the laminated glass sheets may the same thickness or a differentthickness. For example, the thickness of an individual glass sheet maybe from about 0.5 mm to about 3 mm, about 1 mm to about 3 mm, or about 1mm to about 2 mm.

FIG. 1 is a diagram showing an example structure of a laminated glassaccording to an aspect of the present disclosure. As shown in FIG. 1,laminated glass 100 includes three layers. The first layer is a bottomlayer 102, which is a glass sheet. The second layer is an interlayer 104which is also referred to as interlayer film 104. The third layer is anupper layer 106 which is also a glass sheet. Bottom layer 102 and upperlayer 106 may also be referred to as first layer 102 and third layer106, respectively. The laminated glass 100 has an outer area 110 formedby an outer edges of a perimeter 108 of the laminated glass 100 and amiddle area 112 of the laminated glass 100 that is the area in themiddle of the laminated glass having a size of 50 mm×50 mm.

FIG. 2(a) shows laminated glass in which the interlayer has “poor flow.”In example structure 200, there is gap between upper layer 106 andinterlayer 104. FIG. 2(b) shows laminated glass wherein the interlayerhas “good flow.” In example structure 202, the good flow is such thatthere is no gap between upper layer 106 and interlayer 102. Increasedflow results in the interlayer being able to more readily fill the gaps.This prevents moisture from penetrating between layers 102, 104, and106, thereby preventing delamination of the laminated glass.

FIG. 3 illustrates a process for preparing PVB in a preferred embodimentof the present invention. In S300, polyvinyl alcohol (PVA) resin isdissolved in water and heated to provide a PVA solution. In S302, thePVA solution of S300 is cooled to about 10° C. or lower. In S304,hydrochloric acid (HCl) is added to the PVA solution of S302 andstirred. In S306, n-butyraldehyde is added to the solution of S304 andis stirred to provide PVB resin. In S308, the PVB resin of S306 isheated to about 53° C. (e.g., about 44° C. to about 60° C.) andmaintained at this temperature for about 4 hours. In S310, the PVB resinis cooled to at least 35° C. and neutralized with sodium bicarbonate. InS312, the PVB resin is separated, washed with water, and dried.

FIG. 4 illustrates a process for preparing an interlayer film accordingto the instant disclosure. In S400, plasticizer, PVB resin, and metalsalts are combined. In S402, the mixture of plasticizer, PVB resin, andmetal salts is kneaded and cooled to ambient temperature to provideplastic blocks. In S404, the plastic blocks of S402 are pressed with ahot-press machine to provide an interlayer film.

FIG. 5 illustrates a process for preparing laminated glass according tothe instant disclosure. In S500, an interlayer film is interposedbetween a pair of transparent float glass sheets. In S502, a hot-pressis used to prepress the laminated glass sample. In S504, is autoclavedand cooled to provide laminated glass.

Determination of Average Molecular Weight

The Mw of the PVB resin can be determined according to the followingprocedure. A sample of interlayer film (0.08 g) is dissolved in 15 mL oftetrahydrofuran (THF) and analyzed by Gel Permeation Chromatography(GPC) and the molecular weight is calculated from the ratio of an areacorresponding to polystyrene standards (Waters PS STD). The followingGPC parameters are used:

-   -   Device: Waters 1515 PUMP system    -   Detector: Waters 2414 RI    -   Elution Condition: 1.0 mL/min, THF    -   Column: Wateres Styrage HR5 THF, Waters Styrage HR4 THF, Waters        Styrage HR3 THF, Waters STyrage HR1 THF

Determination of Flow

Flow is a measurement of deformation (reduction of sample thickness)when a load pressure is applied to a sample surface in the thicknessdirection, upon heating from an initial temperature to a finaltemperature, measured using a thermomechanical analysis apparatus. Aninterlayer film sample that has been stored in a desiccator is cut intoa disc having a diameter of 6 mm. The disc is interposed between twoplates and placed into a thermomechanical analyzer, for example, a TMAQ400 Texas Instrument with an expansion probe having a diameter of 2.8mm and a Force of 1.0 N. The disc is heated from 25° C. to 145° C. at aheating rate of 10° C. per minute. The deformation (reduction of samplethickness) between 45° C. and 135° C. is measured and the flow iscalculated by subtracting the thickness of the disc at 135° C. from thethickness of the disc at 45° C.

Determination of Pummel Adhesion Value

Adhesion of interlayer films to glass is measured using a pummeladhesion test, which is routinely used for quality control purposes inthe laminated glass industry. A laminated glass sample (glass/interlayerfilm/glass) is prepared, conditioned at −18° C. for 2 hours and pummeledby an automatic pummel machine at a temperature of 20 to 25° C. Thepummeling is carried out in the span of 3 minutes. The degree of exposedinterlayer film of the pummeled laminated glass sample is evaluated andcompared to standard samples. There is one standard sample for eachpummel level. The pummeled test sample is compared with the standardsamples of each pummel level to determine the pummel level of thepummeled test sample.

A laminated glass sample (150 mm wide×300 mm long) is prepared andpummeled with automatic pummel machine (e.g., GOTECH, Taiwan) having a32 mm hammer with a weight of about 1 lb. The sample is pummeled at ahorizontal interval of 9 mm and a vertical interval of 10 mm with apummel force of 94 lb-cm/sec. The degree of exposure is then determinedand categorized on a 10 point scale, shown in table 1 as below:

TABLE 1 Degree of Pummel Adhesion Exposure Value 95% 0 85% 1 75% 2 65% 355% 4 45% 5 35% 6 25% 7 15% 8 Less than 5% 9

Determination of Delamination

The laminated glass sample (150 mm wide×300 mm long) is prepared andmaintained at 50° C. and 95% relative humidity (RH) for 28 days.Delamination of the edges of the laminated glass samples is determinedby the naked eye at room temperature. Twenty pieces of the laminatedglass samples are visually inspected for bubbling and/or delamination,and ranked according to the table 2 as below.

TABLE 2 Delamination test ⊚ No bubbling or delamination ◯ Nodelamination but some bubbling X Bubbling and delamination

Long-Term High Temperature & High Moisture Testing

To determine the influence of long-term high temperature and highmoisture on the adhesive properties of laminated glass, the laminatedglass is manufactured and immediately maintained at 50° C. and 95%relative humidity (RH) for 28 days. After 28 days at 50° C. and 95% RH,the laminated glass is subjected to pummel adhesion testing, asdescribed above.

Implementation of the present disclosure is provided by way of thefollowing examples. The examples serve to illustrate the technologywithout being limiting in nature.

Example 1 Preparation of Polyvinyl Butyral Resin

100 g of polyvinyl alcohol (PVA) having a degree of polymerization of1,700 to about 1,800, was dissolved in 807 g of water and heated to 95°C. to provide a PVA solution. The PVA solution was cooled to 10° C. and64 g of hydrochloric acid (HCl) was added. After mixing for 10 minutes,54 g of n-butyraldehyde was added and the mixture stirred for 15 minutesto form polyvinyl butyral (PVB). The mixture containing the PVB washeated to 53° C. and maintained at this temperature for about 4 hours.After about 4 hours, the mixture was cooled to 35° C. and neutralizedwith sodium bicarbonate. The PVB was separated, washed, and dried.

Example 2 Preparation of Interlayer Film

A mixture was prepared by combining 36-42 parts by weight of aplasticizer (3GO, triethylene glycol bis-(2-ethylhexanoate)) with about100 parts by weight of a PVB resin (of Example 1) and metal salt (10-200ppm of sodium ion or potassium ion in the final interlayer film). Themixture was kneaded at 35 rpm with a mixing machine (Brabender®,Germany, Mixer 50 EHT) at 120° C. for 15 minutes and cooled to ambienttemperature to provide plastic blocks. The plastic blocks were pressedwith a hot-press machine (GOTECH, Taiwan, GT-7014-A) at 150° C. for 3minutes to provide a film having a thickness of 0.76 mm.

Example 3 Preparation of Laminated Glass

The film of Example 2 having a thickness of 0.76 mm was interposedbetween a pair of float glass sheets to provide a laminated glasssample. Clean float glass (thickness 2 mm, manufactured by Taiwan GlassInd. Corp.) or SYP F Green Tinted Glass (thickness 2 mm, manufactured byShanghai Yaohua Pilkington Glass Group Co., Ltd.) was used. Each glasssheet was 150 mm wide and 300 mm long. A hot-presser (GOTECH, Taiwan,GT-7014-A) was used to prepress the laminated glass sample at 150° C.for 3 minutes. Following the prepress procedure, the laminated glasssample was autoclaved at 13 bar and 135° C. for 120 minutes andsubsequently cooled to ambient temperature to complete the laminationprocess, and thus providing the laminated glass samples 1 to 8 andcomparative samples C-1, C-2, and C-3. The corresponding results areshown in table 3.

1 2 3 4 5 6 7 8 C-1 C-2 C-3 Average degree of polymerization of 17001700 1800 1800 1700 1800 1800 1800 1700 1700 1700 PVB resin Molecularweight of PVB resin 180952 186567 199161 201360 185673 197812 189485178898 215533 226270 207934 Amount of PVB resin having a Mw 16.8% 17.6%15.4% 12.8% 15.3% 16.2% 17.8% 18.5% 15.6% 14.8% 5.6% of less than 50,000Amount of PVB resin having a Mw  6.4%  5.7%  6.8%  6.4%  6.5%  6.2% 4.8%  6.5%  5.9%  6.5% 6.3% of greater than 800,000 Amount ofplasticizer (PHR) 42 45 40 40 38 40 43 42 42 42 36 Amount of Na⁺ metalsalt (ppm) 20 10 40 20 10 20 15 21 60 100 35 Amount of K⁺ metal salt(ppm) 5 30 20 0 0 5 32 22 70 160 39 Flow (um) 296 304 274 259 264 283323 347 284 277 198 Pummel adhesion value of middle area 6 5 4 5 7 5 6 57 3 5 Pummel adhesion value of outer area 6 5 4 5 7 5 6 5 7 3 5Long-Term High Pummel adhesion value 6 5 4 5 7 5 6 5 7 3 5 Temperature &of middle area Hight Moisture Pummel adhesion value 9 9 9 9 9 9 9 9 7 35 Testing of outer area Difference of pummel 3 4 5 4 2 4 3 4 0 0 0adhesion value betweem middle area and outer area Detamination test ◯ ⊚⊚ ◯ ◯ ⊚ ◯ ◯ X X X

The results shows that the delamination test in samples 2, 3, and 6 areno bubbling or delamination and in samples 1, 4, 5, 7, and 8 are nodelamination but some bubbling. While the delamination test incomparative samples C-1, C-2, and C-3, the laminated glasses exhibitedbubbling and delamination.

Furthermore, the pummel adhesion value of the outer area of thelaminated glass samples 1 to 8 are higher after the laminated glasssamples are maintained at 50° C. and 95% relative humidity (RH) for 28days than before the laminated glass samples 1 to 8 are maintained at50° C. and 95% relative humidity (RH) for 28 days. In other words,maintaining the laminated glass samples 1 to 8 at a temperature of 50°C. and 95% relative humidity (RH) for 28 days results in the pummeladhesion value of the outer area of the laminated glass increasing.However, this result cannot be observed in the comparative samples (i.e.C-1, C-2, and C-3). As can be seen, the pummel adhesion values of thelaminated glass samples 1 to 8 increased by 2 to 5. Especially in thelaminated glass sample 3, the initial pummel adhesion value (in edge) of4 increased to 9.

As above, the present invention provides the interlayer film and thelaminated glass comprising the same, wherein the interlayer filmsexhibit improved adhesive properties, which result in improvements inthe quality and durability of the laminated glass that incorporates theinterlayer films. For example, delamination of the interlayer films isavoided. Furthermore, the interlayer films result in laminated glassbeing surprisingly resistant to high moisture and high temperatureconditions, even for prolonged periods.

The terms “comprising,” “having,” and “including” are used in theiropen, non-limiting sense.

The terms “a” and “the” are understood to encompass the plural as wellas the singular. The expression “at least one” means one or more andthus includes individual components as well as mixtures/combinations.

The term “directly” can be used in conjunction with terms such as “to”or “on” to result in phrases such as “directly on” and “directly “to.”Such phrases may be especially useful when referring to components orlayers and their relationship to one another. This phraseology (i.e.,phraseology using the modifier “directly”) indicates that components orlayers that are “directly on” one another or applied “directly to” oneanother are in physical contact with each other such that no interveningcomponent(s) or layer(s) is present. For example, if layer A is directlyon layer B, layer A and layer B are in physical contact with each otherand no intervening layer (such as a layer C) can lie between layer A andlayer B.

All ranges and values disclosed herein are inclusive and combinable. Forexamples, any value or point described herein that falls within a rangedescribed herein can serve as a minimum or maximum value to derive asub-range, etc.

All publications and patent applications cited in this specification areherein incorporated by reference, and for any and all purposes, as ifeach individual publication or patent application were specifically andindividually indicated to be incorporated by reference. In the event ofan inconsistency between the present disclosure and any publications orpatent application incorporated herein by reference, the presentdisclosure controls.

Unless otherwise defined herein, scientific and technical terms used inconnection with the present application shall have the meanings that arecommonly understood by those of ordinary skill in the art. Further,unless otherwise required by context, singular terms shall includepluralities and plural terms shall include the singular.

It should be understood that this invention is not limited to theparticular methodology, protocols, and reagents, etc., described hereinand as such may vary. The terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to limit thescope of the present invention, which is defined solely by the claims.

The invention claimed is:
 1. An interlayer film comprising: (a)polyvinyl butyral (PVB) resin having an average molecular weight (Mw) asmeasured by Gel Permeation Chromatography (GPC) from about 175,000 toabout 210,000 Dalton; and (b) about 30 to about 50 parts per hundred(pph) of a plasticizer.
 2. The interlayer film of claim 1 having a flowof at least 250 μm, wherein the flow is a reduction in thickness of a 6mm diameter sample of the interlayer film calculated by subtracting thethickness of the sample at 135° C. from the thickness of the sample at45° C. when placed into a thermomechanical analyzer having an expansionprobe of diameter 2.8 mm and a Force of 1.0 N.
 3. The interlayer film ofclaim 1, further comprising: (c) a sodium salt, a potassium salt, or amixture thereof, in a positive amount up to about 80 ppm as sodiumcontent, potassium content, or a mixture thereof.
 4. The interlayer filmof claim 3, wherein the sodium salt does not exceed 40 ppm as sodiumcontent and the potassium salt does not exceed 40 ppm as potassiumcontent.
 5. The interlayer film of claim 1, wherein the PVB resincomprises at least 10 wt. % of PVB having a Mw of less than 50,000. 6.The interlayer film of claim 1, wherein the polyvinyl butyral resin hasa degree of butyralization of 60 to 80 mol. %.
 7. The interlayer film ofclaim 1, wherein the plasticizer is selected from monobasic acid esters,polybasic acid esters, organic phosphoric acids, organic phosphorusacids, or a mixture thereof.
 8. The interlayer film of claim 1, whereinthe plasticizer is selected from dipropylene glycol dibenzoate,2,2,4-trimethyl-1,3-pentanediol dibenzoate, triethylene glycoldi-(2-ethylhexanoate), tetraethyleneglycol di-(2-ethylhexanoate),triethylene glycol di-(2-ethylbutyrate), triethylene glycoldiheptanoate, tetraethylene glycol diheptanoate, dihexyladipate,dioctyladipate, hexyl cyclohexyladipate, diisononyladipate,heptylnonyladipate, dibutylsebacate, triethylene glycolbis(2-ethylhexanoate)(3GO), tetraethylene glycol di-2-ethylbutyrate(4GH), bis[2-(2-butoxyethoxy)ethyl] adipate (D600), or a mixturethereof.
 9. The interlayer film of claim 3 comprising one or more sodiumsalts selected from sodium perchlorate, sodium formate, sodium acetate,sodium 2-ethylbutyrate, sodium 2-ethylhexanoate, or a mixture thereof.10. The interlayer film of claim 3 comprising one or more potassiumsalts selected from potassium perchlorate, potassium formate, potassiumacetate, potassium 2-ethylbutyrate, potassium 2-ethylhexanoate, or amixture thereof.
 11. The interlayer film of claim 2 having a flow of atleast 250 μm to about 500 μm.
 12. The interlayer film of claim 1 havinga thickness of about 0.3 mm to about 1.5 mm.
 13. The interlayer film ofclaim 1, wherein the interlayer film interposed between two glass sheetsforms laminated glass having a pummel adhesion value that is greater inan outer area of the laminated glass than in a middle area of thelaminated glass after the laminated glass has been maintained at 50° C.and 95% relative humidity (RH) for 28 days, the outer area of thelaminated glass being the area formed by outer edges of a perimeter ofthe laminated glass and extending inward toward the center of thelaminated glass by a distance of 5 mm, and the middle area of thelaminated glass is an area in the middle of the laminated glass having asize of 50 mm×50 mm.
 14. Laminated glass comprising an interlayer filmof claim 1.